Generally, fine particles generated during semiconductor process are a factor that greatly influences manufacturing yield in the semiconductor process where a fine pattern process is required. Most semiconductor processes are performed under lower pressure, and require a particle measurement apparatus operated under low pressure. Particularly, a chemical vapor deposition process has a large part of the semiconductor process. Therefore, in the chemical vapor deposition process, a technology for immediately removing pollutants through real-time monitoring for particle occurrence is necessary to prevent occurrence of defects caused by the fine particles.
In the meantime, a particle beam mass spectrometer is an apparatus for separating gas and particles in an environment where gas and particles are mixed, and for measuring the size of ultra-fine particles by using an electrical filter after ionizing the particles separated from the gas.
In a working environment of the semiconductor process, etc. performed in a vacuum state under low pressure, gas and ultra-fine particles are mixed, and in this case, a particle beam mass spectrometer may be used as an apparatus for monitoring the particle content in real-time.
In regard to manufacturing a particle beam mass spectrometer, Korean patent No. 10-1104213 (9 Jan. 2012) disclosed a particle beam mass spectrometer operated by using an electron gun having high efficiency without loss of thermal electrons in a low-pressure region, and the particle beam mass spectrometer can reduce the use pressure of the particle beam mass spectrometer by using a high efficiency electron gun, thereby reducing manufacturing costs of the apparatus. In addition, Korean patent No. 10-1360891 (12 Feb. 2014) disclosed an apparatus for simultaneously realizing both a function of a conventional particle beam mass spectrometer (PBMS) and a function of a scanning electron microscope (SEM).
However, despite the conventional technology including the related art, in the particle beam mass spectrometer according to the conventional technology, detection is performed only when charged particles are cations. Therefore, it is impossible to obtain information in a case where charged particles are anions. In addition, there is a drawback in that only a mass/charge ratio (M/Z) value of a particular range at a particular time can be measured.
Therefore, there is a need for development of a particle beam mass spectrometer that has a new structure, whereby cations and anions can be separated according to the choice of a user and simultaneous measurement of the cations and anions can be performed, and that can measure a total amount of all ions, thereby providing a user with various pieces of information about the size of the fine particles.